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Prognostic significance of programmed ventricular stimulation in patients surviving complicated acute myocardial
A K Bhandari1, J Widerhorn, P T Sager
1Department of Medicine, Los Angeles County/University of Southern California Medical Center.
Insights
Programmed ventricular stimulation effectively identifies survivors of complicated myocardial infarction at high risk for sudden cardiac death. Inducible sustained ventricular tachycardia combined with heart failure significantly increases arrhythmic event risk.
Area of Science:
- Cardiology
- Electrophysiology
- Critical Care Medicine
Background:
- Survivors of complicated myocardial infarction face elevated risks of sudden cardiac death and ventricular arrhythmias.
- Identifying high-risk patients is crucial for targeted interventions and improved outcomes.
Purpose of the Study:
- To evaluate the utility of programmed ventricular stimulation in risk stratification of myocardial infarction survivors.
- To determine predictors of arrhythmic events and cardiac mortality in this patient population.
Main Methods:
- Prospective study of 86 myocardial infarction survivors with complicated presentations.
- Prehospital discharge programmed ventricular stimulation, cardiac catheterization, and 24-hour ECG monitoring.
- Multivariate analysis to identify independent predictors of adverse events.
Main Results:
- Sustained ventricular tachycardia was inducible in 22% of patients.
- Inducible sustained ventricular tachycardia was associated with a significantly higher incidence of arrhythmic events (32% vs. 7%).
- Inducible sustained ventricular tachycardia and Killip class III/IV heart failure independently predicted arrhythmic events, with a 38.4% event rate when both were present.
Conclusions:
- Programmed ventricular stimulation is a valuable tool for risk stratifying survivors of complicated myocardial infarction.
- The combination of inducible sustained ventricular tachycardia and severe heart failure identifies a particularly high-risk subgroup.
- Low left ventricular ejection fraction was the strongest predictor of overall cardiac mortality.
Abstract:
In survivors of complicated myocardial infarction, the inducibility of sustained ventricular tachycardia may help identify a subset that is at increased risk for subsequent sudden cardiac death or spontaneous sustained ventricular tachycardia. We performed prehospital discharge programmed ventricular stimulation in 86 survivors of acute myocardial infarction complicated by heart failure, angina pectoris, or nonsustained ventricular tachycardia. These patients also underwent cardiac catheterization with coronary angiography and 24-hour ambulatory ECG recording. Programmed ventricular stimulation induced sustained ventricular tachycardia in 19 patients (22%) and ventricular fibrillation in six (7%) and did not induce these arrhythmias in 61 patients (71%). During an average follow-up of 18 +/- 13 months, 11 patients had arrhythmic events (seven sudden death and four nonfatal spontaneous sustained ventricular tachycardia) and 10 patients had nonsudden cardiac death. The total cardiac mortality rate was 20%. Arrhythmic events occurred in 32% of the 19 patients with inducible sustained ventricular tachycardia compared with 7% of the remaining 67 patients (p less than 0.003). By multivariate analysis the occurrence of arrhythmic events was independently predicted by both inducible sustained ventricular tachycardia and Killip class III or IV heart failure. The risk of arrhythmic events was 4.4% in the absence of both variables versus 38.4% (p less than 0.001) when both variables were present. The total cardiac mortality rate was best predicted by low left ventricular ejection fraction (less than 30%). Thus programmed ventricular stimulation is useful in risk stratification of survivors of complicated acute myocardial infarction. The prognostic utility appears to be particularly high in patients with infarction complicated by Killip class III or IV heart failure.